An image display device, i.e., head-mounted display, fixed to the head or face of a user who observes an image is known. The head-mounted display is provided with an image display unit on both the right and left eyes and is configured to be capable of controlling visual and auditory perception using together with a headphone. The configuration for blocking the outside world entirely when it is worn on the head augments virtual reality during viewing. Furthermore, the head-mounted display is capable of projecting a different video image onto each of the left and right eyes and is capable of presenting a 3D image by displaying an image having parallax on the left and right eyes.
This type of head-mounted display forms a virtual image on the retina of the eye to allow the user to observe it. In this regard, the virtual image is formed on the side of an object in a case where the object is situated closer to the lens than the focal length. In one example, there is developed a head-mounted display that forms an enlarged virtual image of a displayed image on the user's pupil by placing a virtual image optical system of a wide viewing angle to be spaced by 25 millimeters away from the front of the pupil and by placing a display panel having a size of the effective pixel range of about 0.7 inches further in front of the wide viewing angle optical system (e.g. see Patent Literature 1).
Moreover, the user is able to observe an image obtained by clipping a part of the wide-angle image using this type of head-mounted display. In one example, there is developed a head-mounted display that allows reality experience of a video image of the whole space of 360 degrees to be achieved by installing a head motion tracking device including a gyro sensor or the like on the head and by causing it to track the movement of the user's head (see Patent Literatures 2 and 3). The movement of a display region in the wide-angle image to cancel the head's movement detected by a gyro sensor makes it possible to reproduce an image that tracks the head's movement, and thus the user experiences as if he looks a panoramic view of the entire space.
Furthermore, there are also known first person view (FPV) techniques that pilot while viewing a first person viewpoint (pilot viewpoint) image captured by a wireless camera mounted on a radio-controlled device such as a helicopter. In one example, a moving object control device composed of a moving object equipped with an image capturing device and a wearable PC for remotely controlling the moving object through an operator's operation is developed (e.g. see Patent Literature 4). The moving object side receives a signal for controlling the moving object's operation to control its own operation, receives a signal for controlling an image capturing device equipped thereon to control the image capturing operation, and transmits video and audio signals outputted from the image capturing device to the wearable PC. Meanwhile, the wearable PC side generates a signal for controlling an operation of the moving object in response to the operator's operation, generates a signal for controlling an operation of the image capturing device in response to the operator's voice. The wearable PC side transmits wirelessly the generated signal to the moving object, receives wirelessly a signal outputted from the image capturing device, reproduces a video signal, and displays it on a monitor screen.
Furthermore, a network system is developed in which a radio-controlled car equipped with a three-dimensional stereo camera for medium-to-long distance and a three-dimensional stereo camera for short distance transmits a three-dimensional composite image to be displayed on a controller side (e.g. see Patent Literature 5). A network system is developed in which a model device captures an image of an area in front of the model device and a controller side receives information on the image, position, and direction of the model device, generates a virtual image based on the position and direction, and displays it (e.g. see Patent Literature 6).